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Light in the Dark

Dec 30, 2012

For decades, astronomers have grappled with their inability to decipher the universe's darkest secret: the identity of most of its matter. It's not the same stuff as the ordinary atomic variety of matter common on Earth. Atoms or their parts -- such as protons and neutrons -- make up less than 17 percent of the mass in the cosmos. All the rest is "dark" -- invisible to eyes and telescopes, its presence deduced by its gravitational tug on stars and galaxies (SN: 8/28/10, p. 22). With a deluge of new data already in hand, and more precise probes in the works, learning the identity of dark matter may just be a matter of time.